int exp = Convert.ToInt16(txtSecondNumber.Text); //Check the numbers if (txtFirstNumber.TextLength > 0 && txtSecondNumber.TextLength >0) { //Check that the second number is an integer try { exp = (int.Parse(txtSecondNumber.Text)); } //If it is not an integer, give an error catch(FormatException) { MessageBox.Show(" Second number must be a integert value.", "Entry Error"); txtSecondNumber.Focus(); } } //If There is data, do the math { decimal result = 1; for (int i = 0; i < exp; i++) result*=exp; txtResult.Text = result.ToString("c"); }